RFC: remove HTTP tools from default build

[keithw]

The mm-webrecord and mm-webreplay parts of mahimahi seem to be less relevant in a world where (a) SNI is increasingly required and (b) HTTP/2 and HTTP/3 are now prevalent. (They have only ever supported SNI-less TLS and HTTP/1.1.) They are also using deprecated OpenSSL APIs (#155).

Are there objections to removing these from the default build (and Debian/Ubuntu package), and having mahimahi just become the link emulation tools (mm-delay, mm-link, etc.)? This would fix #155 in a simple way.

@ravinet